Bertrand Russell in "My Philosophical Development" claimed he converted to neutral monism in 1919, in the essay "On Propositions." I question whether Russell was really a complete neutral monist in the style of Mach and James and conclude that he was not. Russell's lingering commitment to image propositions and a linguistic theory of meaning and truth and falsity separate him from the more naturalistic causal theory of knowledge and error one finds in James and Mach.